Droperidol vs. Prochlorperazine for Benign Headache

Many emergency physicians merely classify the undifferentiated headache, a common emergency department (ED) complaint, as either serious or benign, with the great majority being considered benign. This study compared the efficacy of droperidol vs. prochlorperazine in the treatment of ED patients clinically diagnosed with benign headaches.

This was a prospective, single-blind trial performed in a busy, urban ED. A convenience sample of consenting patients ages 18-60 years were enrolled if they had a "benign" headache as defined by the examining physician, and if the physician planned to treat the headache with either of the two medications. These patients were to be without an identifiable etiology of their headache from history, physical, laboratory results, or imaging studies. Patients not deemed to have undifferentiated benign headaches included, but were not limited to, those diagnosed with traumatic headaches, subarachnoid or intracranial hemorrhage, meningitis, cranial tumor, sinusitis, dental pathology, temporomandibular joint dysfunction, glaucoma, or systemic infection.

Enrolled patients were randomized to receive either droperidol 5 mg IM or 2.5 mg IV, or prochlorperazine 10 mg either IM or IV. The route of administration was decided by the treating physician prior to randomization. Prior to receiving medication, and again at 30 and 60 minutes, patients were asked to complete a 100 mm visual analog scale (VAS) ranging from no pain (0) to most severe pain (100). Physicians were required to record side effects of the medications and whether further medication was required. Side effects were classified as dyskinesia, akathisia, hypotension, arrhythmia, decreased level of consciousness, or other. Patients were contacted by telephone 24 hours after the ED visit to assess for rebound headaches or delayed medication side effects.

One hundred sixty-eight patients completed the study, with 82 receiving droperidol and 86 receiving prochlorperazine. Forty-nine (60%) of the patients in the droperidol arm received their medication IM, and 57 (66%) of the patients in the prochlorperazine arm received their medication IM. The two groups were not statistically different in initial VAS score, gender, age, home analgesic use prior to presentation, percentage of patients with previously diagnosed migraine headaches, or rate of IM medication administration.

Sixty minutes after medication administration, the mean decrease in VAS score was 81% (from 79.8 mm to 16.3 mm) for droperidol and 70% (from 74.3 mm to 28.9 mm) for prochlorperazine (P = 0.001). At 60 minutes, 90% of the patients receiving droperidol and 69% of the patients receiving prochlorperazine had at least a 50% reduction in their VAS scores (P = 0.017). No difference between IM dosing and IV dosing was detected. Side effects, including dystonia, akathisia, and decreased level of consciousness, were seen in 15% of patients receiving droperidol and 10% of patients receiving prochlorperazine. Of the 13 patients with side effects in the droperidol group, one had dystonia, five had akathisia, and seven had decreased level of consciousness requiring between 95 minutes and 4.5 hours of observation prior to discharge. Of the eight patients with side effects in the prochlorperazine group, seven had akathisia and one had decreased level of consciousness. On phone follow-up, similar numbers of patients had rebound headaches.

The authors conclude that droperidol is more effective than prochlorperazine in relieving pain associated with benign headaches.

They report that the study was not powered or designed to draw any conclusions regarding adverse effects or routes of administration, and believe future studies are warranted.

Commentary by Jacob W. Ufberg, MD

This is a well-designed study which shows that droperidol is statistically superior to prochlorperazine for relieving the pain associated with benign headaches. However, the use of the arbitrary cutoff of 50% reduction in VAS score inflates the numerical superiority of droperidol from a difference of 81% vs. 70% decrease in absolute VAS score to a much more impressive difference (90% vs 69%) in number of patients achieving this artificial benchmark.

Additionally, the final VAS scores at 60 minutes were 16.3 mm for the droperidol group and 28.9 mm for the prochlorperazine group. While this difference is statistically significant, the clinical significance of this difference is unclear. Very few studies have attempted to quantify the minimum clinically significant VAS difference. One prior study by Todd and Funk examined physician-assigned VAS scores (rather than patient-assigned, as in this study), and estimated that changes of less than 18 mm may have little clinical importance.

In conclusion, it appears that droperidol offers a statistical and likely (but not definite) clinical advantage in the treatment of benign headaches in the ED. We must remain aware, however, of the increased rate of sedation among patients receiving droperidol and the possibility of prolonged length of stay when using this medication.

Dr. Ufberg, Assistant Professor of Emergency Medicine, Department of Emergency Medicine, Temple University School of Medicine, Philadelphia, PA, is on the Editorial Board of Emergency Medicine Alert.

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